Approximately at which point does the electronic oil level system indicate that a top-up is needed and does it states the quantity required?
With 3k miles from new, the screen on my 640i is indicating just over half full, but it's still green and there are no other indications.
My instinct tells me to add oil now, but without knowing how much is required, I could easily overfill.
My previous two BMWs were extremely oil-frugal 6cyl diesels and I have no experience of modern petrol engine oil consumption.
Any advice much appreciated - many thanks.

Okay, the top box above the max line should, for the most part, not be green as that would be acceptable but still slightly overfilled.

Now, the first box below the max line and the first box above the min line and all the boxes in between, when combined, represents one quart.

So, if you wait until the oil level gets to the box above the minimum line then you can dump a whole quart without fear. This may or may not cause the box above the max line to turn green.

Finally, the box below the min line should always be green. If it us not green then you will turn on the idiot lights.